Continuous recording of accommodation and pupil size using the Shin-NipponSRW-5000 autorefractor

A newly released commercial autorefractor, the Shin-Nippon SRW-5000 (Japan) , has been found to be valid compared to subjective refraction and repeatab le over a wide prescription range. Its binocular open field-of-view allows the accommodative state to be monitored while a natural environment is view ed. In conventional static mode, the device can take up to 45 readings in 1 min using digital image analysis of the reflected retinal image of a measu rement ring. Continuous on-line analysis of the ring provides high (up to 6 0 Hz) temporal resolution of the refractive state to an accuracy of <0.001 D. Pupil size can also be analysed to a resolution of <0.001 mm. The measur ement of accommodation and pupil size was relatively unaffected by eccentri city of viewing up to +/-10 degrees and instrument focusing inaccuracies of +/-5 mm. The resolution properties of the analysis are shown to be ideal f or measurement of dynamic accommodation and pupil responses. (C) 2001 The C ollege of Optometrists. Published by Elsevier Science Ltd. All rights reser ved.